Lack of effect of laboratory-provoked anxiety on plasma homovanillic acid concentration in normal subjects

The present study was undertaken to investigate if acute anxiety can affect plasma concentrations of homovanillic acid (pHVA). Since elevated pHVA levels have been associated with severity of schizophrenic symptoms, the results of this study will help determine if the pHVA elevations are directly related to psychosis or if anxiety is also a contributory factor. Anxiety was provoked in 10 young normal subjects by a combined paradigm of mental arithmetic task and threat of electrical shock. A significant increase in self-ratings of anxiety, blood pressure, and plasma levels of norepinephrine, 3-methoxy-4-hydroxyphenylethyleneglycol and growth hormone indicated that the paradigm used was effective in provoking anxiety; however, anxiety did not affect pHVA concentrations. The results may support the notion that increased pHVA levels in severely ill schizophrenic patients are related to the schizophrenic pathophysiology rather than to anxiety.